Mechanic&#39;s creeper



June .24, 1941. J. H. HECKMAN MECHANIGYCREEPER Filed Feb; 10, 1941 2Sheets-Sheet 1 June 24, 1941. J. HECKMAN 2,245,628

MECHANIC S CREEPER Filed Feb. 10, 1941 2 Sheets-Sheet :2

7 l c Y I I II i a Patented June 24, 1941 UNlTED STAT Es PATENT OFFICEMEonsNIcs CREEPER Joseph H. Heckman, Chicago, Ill. Application February10, 1941, Serial No. 378,292 4 claims. (Cl. 280 -615) This inventionrelates to a mechanics creeper,

and more particularly to a creeper of anim proved type such that it isnot injured by excessive overload, as when itis run over by the wheelofacar. i

One feature of this invention is that it provides an exceptionallysturdy and satisfactory creeper; another feature of this invention is,that its body is of sufficient strength to resist anticipated overloads,as the wheel of an automobile, and provision is made for protecting thesupporting Wheels of the creeper under such. conditions; yet anotherfeature of this invention is that under normal usage the creeperisasfully and easily maneuverable as the conventional creeper, and capableof passing over minor obstructions, as a crack in the floor or a handwrench; other features and advantages of this, invention will beapparent from the following specification and the drawings, in which: ii

Figure 1 is a topplan view of a mechanics creeper embodying myinvention; Figure 2 is a side elevation of the creeper shown in Figurel, partly broken away; Figure 3 is aviewsimilar to that of Figure 2, butshowingthe creeper under abnormal load, as the wheel of a car; Figure 4is an end elevation of the creeper shown in Figure 2; Figure 5 is abottom plan View of the creeper; Figure 6 is a detail fragmentary bottomplan view of the mounting arrangement of one of the casters; and Figure'7 is a fragmentary sectional view along the line 1-1 of Figure 6.

Mechanics creepers, low flat movable supports permitting a mechanic towork convenientlyin a reclining position beneath an automobile, havebeen known and used for some time. These creepers have been open toseveral serious objections, however. One of these objections is that,where conventional small casters are'used at the four corners of thecreeper, accidental overloads (such as those imposed by the wheel of anautomobile) result in either smashing the body of the creeper ordestroying one or more'of the casters.

In order to keep the creeper close enough to the floor on which it is tobe used, these pivotally mounted wheels or casters must be quite small,and their service life is generally very short. In the conventionalcreeper, where four casters are rigidly mounted at the four corners ofthe body of the creeper, the service life of the casters is such thatthey generally must be replaced about once a month in a garage where acreeper is given the customary amount of use.

I have heretofore met this problem of caster breakage by the use ofrelatively large wheels of considerable strength, as dis-closed in myPatent No. 2,148,199, which issued to me on February 21, 1939. Suchwheels were not pivotally mounted with respect'to the body of thecreeper, however, and certain mechanics prefer a creeper with casters,so that the creeper is fully and freely movable in any direction at anytime.

My present invention retains this complete freedom of movement, yetavoids breakage of the creeper body or casters upon accidental overload.I have accomplished this by mounting the casters in such a Way that theyare yieldable under overload. That is, under normal usage the casterscarry the weight of the creeper and the mechanic lying thereon, andmaintain a clearance between the creeper body and the floor which is inthe neighborhood of one-half inch; but under abnormal overload, as thewheel of a car, the casters yieldand retreat into recesses providedtherefor in the [creeper body, so that the creeper body itself comesinto contact with the floor to withstand the abnormal load.

In theparticular embodiment of my invention illustrated herewith thecreeper comprises a body portion having side frame members or bars l0,and Il. These are rigidly held together at appropriate intervals bytransverse cross members fastened beneath the side frame members. Thesecross members are here shown as four in number, and identified as [2,13,14 and I5. The bed of the creeper, designed to support the recliningmechanic, is of thinner material carried by the cross members, and lyingbetween the side frame members. This may be of plywood, for example, andis here identified as It. The body'is also preferably provided, at oneend, with a head rest or cushion l1.

The creeper body is supported, in normal usage, by four pivotallymounted wheels or casters here identified as [8, I9, 23 and'2l. Thesecasters are so mounted that, under no load or the normal load of amechanic, the position of the creeper with respect to its supportingsurface is as illustrated in Figure 2. But the mounting is yieldable, sothat if the creeper is subjected to an abnormal overload, as by beingrun over by the wheel 22 of a car, the relation of the creeper to itssupporting. surface is as illustrated in Figure 3, the abnormal overloadnow being distributed over the entire surface or underside of thetransverse members l2, l3, l4 and i5. It will be understood, of course,that if the wheel of the automobile ran over the extreme end of thecreeper only the casters on that end might yield, and only thetransverse member on that end come into engagement with the floor. Inany event, however, abnormal overloads do not have to be carried by thecasters, but are instead supported directly by the body. The frame andtransverse members of the body are preferably of hardwood, ofconsiderable strength. The proportion of the various parts can bereadily ascertained when it is understood that the .creeper shown isabout three feet long and a little less than one and one-half feet wide.The mounting of each' of the casters is identical, and for convenienceof description only one will be considered in detail. Referring moreparticularly to Figures 6 and 7, it will be seen that the frame memberII is provided near its end with a recess which may be termedkeyholeshaped. This recess comprises a circular portion 23 and anextending portion 24. The'diarne ter of the portion 23 of the opening isa little greater than the outside radius of the circle of the swivellingcaster wheel I8; and its depthis such as to normally partly receive thecaster wheel mounting, with sufiicient reserve or normally unused depthto permitthe caster wheel and its mounting to move up into the recessuntil the underside of the transversemembersof the body contact thefloor on which the creeper rests.

The" yieldable mounting is here shown in a form which I have foundpracticable; although it will be understood that other equivalent'yieldiable mountings for the caster wheel could be used. In my embodiment ofthe invention disclosed herewith a leaf spring is used as a sup port forthe caster. This leaf spring may be a portion of a conventionalautomobile spring leaf, fastened at one end, as by the bolts 25 and 26,to the body of the creepers; and carrying at its other end the caster(8'. The caster plate may be fastened to this end of the leaf spring,

here indicated as 21, by riveting as shown here,

or by bolts. It will be seen that the leaf spring 2'! lies with thecenter portion of its body in the extended portion 24 of the recess inthe frame member, with its outer end lying just within the circularrecess 23.

Casters of the kind which I have used in a practicable embodiment of myinvention have a strength in the neighborhood of 250 pounds each. Thatis, the caster wheels and their swivel mounting will withstand up to 250pounds before breaking or becoming so deformed as to be of no furtheruse. In conjunction with these casters I have chosen a leaf spring ofsuch a strength that 50 or 60 pounds of weight per caster canbesupported before there is any noticeable yield orthe spring; andthereafter the spring yields until; when there is about 150 poundsweight on any one caster and its supporting spring,.the' caster and itsmounting have retreated to the position shown in dotted lines in Figure7, so that any further load is taken directly by the transverse framemembers. With this construction the nor-- mal weight of a mechanisc,distributed over the four casters, results in no appreciable yield oftheir mounting, and the under surface of the creeper body is maintainedwith a clearance of about one-half inch from the floor. Under abnormaloverload, however, the caster wheels retreat or yield to transfer theload to the underside of the transverse frame members. This transfer ofload takes place long before the breaking point of the castersthemselves is reached, so that the casters are never broken or deformed.It is obvious that this provides a very rugged creeper of the castertype, which will protect the casters against destruction from overloads.

While I have described and shown certain embodiments of my invention, itis to be understood that it is capable of many modifications. Changes,therefore, in the construction and arra'ngement may be made withoutdeparting from the, spirit and scope of the invention as disclosed inthe appended claims,

1. A mechanics creeper of the character described, including: a bodyadapted to support a person in reclining position, the entire body beingvery close to the surface on which it is adapted to'be supported andhaving a plurality of recess'es in its under side; wheels forcarryingthe body, said wheels normally lying partially within saidrecesses; and mounting means connecting the wheels to the body, thewheels and mounting means being entirely beneath the body, said mountingmeans being yieldable and of sufficient strength to maintain said bodyspaced from the supporting surface under normal load but sufficien'tlyyieldable that the wheels move further into said recesses to permitcontact of said body with said surface under abnormal load.

2. A mechanics creeper of the character described; including: a bodyadapted to support a.

3 person in reclining position, the body comprising side frame membersof substantial thickness having recesses in their under sides near theirends, and an intermediate supporting portion of lesser thickness;casters for carrying the body, said casters normally lying partiallywithin said recesses; and spring means for mounting said casters' on theunder side of said body, said means being of sufficient strength tomaintain said body spaced from the supporting surface under normal loadbut sufiiciently yieldable that the casters move further into saidrecesses to permit contact of said body with said surface under abnormalload, the casters and spring means being at all times entirely beneaththe body.

3. Apparatus of the character claimed in claim 2, wherein the mountingmeans for each caster is a leaf spring having one end connected to thecaster and the other end connected to the under side of the body.

4. A mechanics creeper of the character described, including: a bodyadapted to support a person in reclining position, the entire body beingvery close to the surface on which it is adapted' to be supported; andwheels beneath the body for carrying it, each wheel being mounted on amember movable with respect to the body and in turn yieldably mountedthereon, portions of the body completely overlying the wheels andmounting and projecting down toward said surface to contact it, underabnormal load, before the yield of the mounting has reached its limit.

JOSEPH H. HECKMAN.

